1. Field of the Invention
The present invention relates to a network address assigning system, in particular, to a network address assigning system for managing addresses of a network and sub-networks such as LAN (Local Area Network), WAN (Wide Area Network), Intra-Net, and Extra-Net.
2. Description of the Related Art
Whenever a node is newly added or moved, terminal addresses/IP addresses of a conventional computer network are individually aligned/changed.
In Japanese Patent Laid-Open Publication No. 9-130421 as a first related art reference of the present invention, a terminal address management system corresponding to a virtual network management method is disclosed. In the terminal address management system, a management table for managing a MAC (Media Area Control) address, VLAN (Virtual Local Address Network) identifier, a switching hub identifier, and a port number is used. The MAC address is used for identifying a LAN board of a computer. In the first related art reference, network addresses are intensively managed by an address server.
In Japanese Patent Laid-Open Publication No. 8-194657 as a second related art reference of the present invention, an IP address automatic assigning system for portable terminals connected to a local area network is disclosed. The system is used for an automatic Internet program apparatus. In the second related art reference, network addresses are intensively managed by an address server.
In Japanese Patent Laid-Open Publication No. 6-062020 as a third related art reference of the present invention, a computer network structuring/modifying system is disclosed. In the system, addresses are changed and reused corresponding to the movement of a node. In the third related art reference, network addresses are intensively managed by an address server.
In Japanese Patent Laid-Open Publication No. 8-204719 as a fourth related art reference of the present invention, an IP address assigning apparatus and an IP address assigning method are disclosed. In the fourth related art reference, terminal addresses are managed by a terminal IP address management server.
In Japanese Patent Laid-Open Publication No. 2-222336 as a fifth related art reference of the present invention, a computer address management system is disclosed. In the fifth related art reference, a terminal inquires a local address of an address server.
In Japanese Patent Laid-Open Publication No. 5-028065 as a sixth related art reference of the present invention, an information processing system is disclosed. In the sixth related art reference, an address management server automatically assigns an address of a client corresponding to an address assignment request issued therefrom.
In Japanese Patent Laid-Open Publication No. 61-123232 as a seventh related art reference of the present invention, an address assigning system for a local area network system is disclosed. The structure of the address assigning system is shown in FIG. 1. Referring to FIG. 1, an address server 1 manages addresses of nodes 10, 11, 12, and 13 of sub-networks 17, 18, and 19 of routing nodes 2, 3, 4, and 5 as well as addresses of routing nodes 2, 3, 4, and 5 of a main-network 16. Thus, for example, whenever a node is added or deleted, the contents of a destination address table for all nodes should be updated. Thus, to flexibly operate the system, the routing nodes 2 to 5 have respective address server functions so as to distributively manage addresses.
In the first related art reference, the address server does not totally manage the full network as a set of routing nodes and sub-networks thereof. In other words, network addresses of the sub-networks cannot be assigned and managed. Thus, the system of the first related art reference cannot handle the movement of a sub-network. In addition, since the address server does not communicate with the routing nodes, network addresses cannot be totally assigned over the network.
In the second related art reference, the address server does not totally manage the network as a set of routing nodes and sub-networks. In addition, addresses of the sub-networks are not assigned and managed. Consequently, the system of the second related art reference cannot handle the movement of a sub-network. In addition, since the address server does not communicate with the routing nodes, network addresses cannot be totally assigned over the network.
In the third related art reference, address servers are disposed corresponding to individual domains. Since terminal addresses are managed in association with node names, the address management servers do not assign and manage addresses of sub-networks.
In the fourth related art reference, network addresses are not managed. In the fifth related art reference, although the address server manages terminal addresses, it does not manage network addresses.
In the sixth related art reference, although the address server manages client addresses, it does not manage network addresses.
In the seventh related art reference, addresses are hierarchically managed corresponding to an expansion or a deletion of a node in a sub-network. However, in the seventh related art reference, the movement of a sub-network and the movement of both a sub-network and a routing node at a time are not mentioned at all.
An object of the present invention is to provide a system that handles the movement of both a routing node and a sub-network thereof at a time and that manages addresses in a multi-home format.
The present invention is a network address assigning system, comprising a plurality of sub-networks directly communicated with each other, a network composed of the sub-networks connected to each other, an address server for managing network addresses of the sub-networks, a plurality of nodes for transmitting and receiving messages over the sub-networks, a plurality of routing nodes each having a node function for transmitting and receiving a message, a router function for transferring a message over the sub-networks, and an address management function for managing addresses of the sub-networks, a change indicator for causing the address server to re-assign network addresses of the sub-networks and for causing the routing nodes to notify the address server of network addresses of the routing nodes, storage for causing the address server to store address information, and a notifier for causing the address server to communicate with the routing nodes and to notify the routing nodes of network address information that has been newly registered/changed.
When the network address information is registered by the change notifier, the address server does not notify the routing nodes of the network address information that has been newly registered/changed.
The routing nodes each have a means for inquiring data of the address server, and a means for obtaining the latest address information of the network.
IP (Internet Protocol) datagram (a kind of packet) is transferred corresponding to a network address assignment table physically stored by the address server and the sub-networks of the routing nodes.
These and other objects, features and advantages of the present invention will become more apparent in light of the following detailed description of a best mode embodiment thereof, as illustrated in the accompanying drawings.